Hydroprocessing of high nitrogen feed using bulk catalyst

ABSTRACT

Methods are provided for hydrotreating high nitrogen feeds with improved results for nitrogen removal, aromatic saturation, and/or sulfur removal. The method includes hydrotreating the feed with a supported hydrotreating catalyst followed by a bulk metal catalyst, the hydrotreated effluent of which can be suitable for use as a feed to an FCC reactor.

CROSS-REFERENCE TO RELATED APPLICATIONS

This invention claims the benefit of U.S. provisional patent applicationNo. 61/283,695, filed on Dec. 8, 2009, the contents of which are herebyincorporated by reference in their entirety.

FIELD OF THE INVENTION

This invention provides a method for hydrotreatment of hydrocarbon feedswith elevated nitrogen contents. This invention also provides a methodfor enhanced utilization of less active catalysts for heteroatomremoval.

BACKGROUND OF THE INVENTION

Crude oils of different origins can contain varying levels ofcontaminants within the feed. In some instances, the contaminant levelsin a crude oil can be characteristic of the regional source of the crudeoil. For example, crude oils extracted from sources in California tendto have high levels of nitrogen contamination. When such a Californiacrude enters a refinery, the high nitrogen levels may impact multipleprocesses within a refinery.

Conventionally, it is known that the amount of nitrogen in a feed cannegatively impact the catalytic activity in hydrotreating processes.This can lead to difficulties, as hydrotreatment is one of the mostprevalent processes used for removal of nitrogen.

U.S. Pat. Nos. 6,162,350 and 7,513,989 describe a bulk metal catalystcomposition that can be used for various types of hydroprocessing.Suitable feedstocks are described as including feeds that contain“substantial” amounts of nitrogen. A feed having a nitrogen content ofat least 10 wppm is noted as an example of a feed containing a“substantial” amount of nitrogen. It is also noted that feeds havinggreater than 500 wppm of nitrogen can be treated. Experimental examplesare also described where a vacuum gas oil feed having a nitrogen contentof 858 wppm is hydrocracking in the presence of a bulk metal catalyst.

U.S. Pat. No. 7,597,795 describes a method for hydrotreating a lubricantoil basestock using a supported hydrotreating catalyst followed by abulk metal catalyst. The feedstock for the process is described ashaving a nitrogen content of up to 0.2 wt %. Examples are provided ofhydrotreating vacuum gas oil feeds with nitrogen contents as high as1573 wppm.

SUMMARY OF THE INVENTION

In one aspect of the invention, a process for hydrotreating a feedstockhaving a relatively high nitrogen content is provided. The methodincludes contacting a hydrocarbon feedstock having a nitrogen content ofat least about 3000 wppm with a supported hydrotreating catalyst underfirst hydrotreating conditions. The hydrotreated hydrocarbon feedstockcan then be contacted with a sulfided bulk metal catalyst under secondhydrotreating conditions to produce a hydrotreated effluent, saidcatalyst comprising a non-noble Group VIII metal molybdate in which atleast a portion, but less than all, of the molybdenum has been replacedby tungsten. Prior to sulfidation, the bulk metal catalyst can berepresented by the formula: (X)_(b)(Mo)_(c)(W)_(d)O_(z), wherein X is anon-noble Group VIII metal, the molar ratio of b:(c+d) is from about0.5:1 to about 3:1, the molar ratio of c:d is greater than about 0.01:1,and z=[2b+6(c+d)]/2.

In another aspect of the invention, another process for hydrotreating afeedstock having a relatively high nitrogen content is provided. Themethod includes contacting a hydrocarbon feedstock having a nitrogencontent of at least about 3000 wppm with a supported hydrotreatingcatalyst under first hydrotreating conditions. The hydrotreatedhydrocarbon feedstock can be contacted with a sulfided bulk metalcatalyst under second hydrotreating conditions to produce a twicehydrotreated feedstock, said catalyst comprising a non-noble Group VIIImetal molybdate in which at least a portion, but less than all, of themolybdenum has been replaced by tungsten. Prior to sulfidation the bulkmetal catalyst can be represented by the formula:(X)_(b)(Mo)_(c)(W)_(d)O_(z), wherein X is a non-noble Group VIII metal,the molar ratio of b:(c+d) is from about 0.5:1 to about 3:1, the molarratio of c:d is greater than about 0.01:1, and z=[2b+6(c+d)]/2. Thetwice hydrotreated feedstock can then be contacted with a supportedhydrotreating catalyst under third hydrotreating conditions to produceat least a thrice hydrotreated effluent. The thrice hydrotreatedeffluent can then be delivered to a fluid catalytic cracking stage.

In another aspect of the invention, a method for effectively utilizingheteroatom removal capability of a bulk catalyst in removing heteroatomsfrom a hydrocarbon feedstock is provided. The method includes:hydrotreating a first hydrocarbon feedstock by contacting the firstfeedstock with a bulk catalyst containing at least three of thefollowing metals: cobalt, nickel, molybdenum, and tungsten (e.g.,nickel, molybdenum, and tungsten), said bulk catalyst in its unusedstate having a relative volumetric catalytic activity forhydrodesulfurization and/or hydrodenitrogenation, with the contactingbeing done under conditions effective to at least partiallyhydrodesulfurize and/or hydrodenitrogenate the first feedstock, whereinthe contacting continues until the bulk catalyst exhibits a relativevolumetric hydrodesulfurization activity of not more than 60% (forexample not more than 55% or not more than 50%) of the relativevolumetric hydrodesulfurization activity in its unused (fresh) state;isolating the hydrotreated first hydrocarbon feedstock; hydrotreating asecond hydrocarbon feedstock by contacting the second feedstock with thebulk catalyst whose relative volumetric hydrodesulfurization activity isnot more than 60% (for example not more than 55% or not more than 50%)of the relative volumetric hydrodesulfurization activity in its unusedstate, with the contacting being done under conditions effective to atleast partially hydrodesulfurize and/or hydrodenitrogenate the secondfeedstock, as well as to hydrodeoxygenate the second feedstock; andisolating the hydrotreated second hydrocarbon feedstock. Advantageously,in this aspect, one or more of the following can be satisfied: thesecond hydrocarbon feedstock can contain at least 10 wt % (for exampleat least 15 wt % or at least 20 wt %) more biocomponent content than thefirst hydrocarbon feedstock; the first hydrocarbon feedstock has apre-treated sulfur content, the hydrotreated first hydrocarbon feedstockhas a post-treated sulfur content, and the post-treated sulfur contentcan be no more than 3.0% (e.g., no more than 2.0%, no more than 1.0%, orno more than 0.5%) of the pre-treated sulfur content; the secondhydrocarbon feedstock has a pre-treated oxygen content and a pre-treatedsulfur content, the hydrotreated second hydrocarbon feedstock has apost-treated oxygen content and a post-treated sulfur content, thepost-treated oxygen content can be no more than 1.0% (e.g., no more than0.5%, no more than 0.3%, or no more than 0.1%) of the pre-treated oxygencontent and/or the post-treated sulfur content can be no more than 3.0%(e.g., no more than 2.0%, no more than 1.0%, or no more than 0.5%) ofthe pre-treated sulfur content; and the isolated hydrotreated firsthydrocarbon feedstock and the isolated hydrotreated second hydrocarbonfeedstock can both be combined with each other and/or with a fuel pool(e.g., a diesel fuel pool).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically shows a reaction system for performing a processaccording to an embodiment of the invention.

FIG. 2 shows nitrogen removal using various catalyst systems.

FIG. 3 shows sulfur removal using various catalyst systems.

DETAILED DESCRIPTION OF THE EMBODIMENTS Overview

Conventional wisdom tells us that bulk metal catalysts are not generallysuitable for processing feeds with nitrogen contents of about 0.3 wt %or greater. The presence of such high levels of nitrogen is believed tosuppress any catalytic advantage provided by a bulk metal catalyst, inrelation to a supported catalyst, for performing hydrodenitrogenation(HDN) and/or hydrodesulfurization (HDS). As a result, conventionalprocesses have focused on using supported catalysts to hydrotreat feedshaving nitrogen contents in excess of about 0.3 wt %.

Feeds with high nitrogen contents can also pose other difficultiesduring hydrotreating. For example, high nitrogen content can alsosuppress catalyst activity for aromatic saturation. This can poseparticular problems for applications such as hydrotreatment prior to afluid catalytic cracking process. Because the conditions in aconventional fluid catalytic cracking process do not result insubstantial amounts of cracking of aromatic compounds, improvements inaromatic cracking and/or saturation in hydrotreating processes prior toa fluid catalytic cracking process are highly desirable.

In various embodiments, a method is provided for hydrotreating feedshaving relatively high nitrogen content with improved nitrogen removal,aromatic saturation, and/or sulfur removal. The method includeshydrotreating the feed with a supported hydrotreating catalyst, followedby contacting with a bulk metal catalyst.

Feedstock

The feedstocks useful according to the invention can, in someembodiments, preferably be relatively high nitrogen content feedstocksincluding a gas oil fraction. In an embodiment, the final boiling pointof such feedstocks can be about 1300° F. (about 704° C.) or less, forexample about 1200° F. (about 649° C.) or less or about 1100° F. (about593° C.) or less. Alternately, a feedstock can be characterized by thetemperature required to boil a specified percentage of the feed. Forexample, the temperature required to boil at least 95 wt % of a feed isreferred to as a “T95” boiling point. Preferably, a feedstock can have aT95 boiling point of about 1300° F. (about 704° C.) or less, for exampleabout 1200° F. (about 649° C.) or less or about 1100° F. (about 593° C.)or less. In some instances, the feed can preferably include gas oilportions and can have an initial boiling point of at least about 400° F.(about 204° C.), for example at least about 450° F. (about 232° C.), atleast about 500° F. (about 260° C.), or at least about 550° F. (about288° C.). Additionally or alternately, the feed can include keroseneand/or diesel boiling range components, resulting in an initial boilingpoint of at least about 200° F. (about 93° C.), for example at leastabout 300° F. (about 149° C.). In another embodiment, the feed can havea T10 boiling point of at least about 300° F. (about 149° C.), forexample at least about 400° F. (about 204° C.), at least about 450° F.(about 232° C.), at least about 500° F. (about 260° C.), or at leastabout 550° F. (about 288° C.). In other embodiments, the feedstock canhave an API gravity of at least about 15, for example at least about 17,at least about 20, or at least about 22. A feedstock suitable forhydrotreatment according to the invention can be a feed for use in afluid catalytic cracking process. Such a feed can typically behydroprocessed in a relatively high severity hydrotreatment stage priorto introduction into the fluid catalytic cracking stage.

The feedstocks to be hydrotreated according to the invention can, insome embodiments, have nitrogen contents previously believed to beunsuitable for processing by a bulk hydrotreatment catalyst. In anembodiment, the nitrogen content of such feeds can be at least about3000 wppm, for example at least about 4000 wppm or at least about 5000wppm. Additionally or alternately, the feed nitrogen content can beabout 8500 wppm or less, for example about 7500 wppm or less or about6000 wppm or less. In an embodiment, feedstreams suitable for use hereincan have a sulfur content from about 100 wppm to about 40,000 wppmsulfur. The sulfur content of the feed can be at least about 500 wppm,for example at least about 1500 wppm, at least about 2500 wppm, at leastabout 5000 wppm. Additionally or alternately, the sulfur content of thefeed can be about 40,000 wppm or less, for example about 30,000 wppm orless, about 15,000 wppm or less, or about 5000 wppm or less.

Optionally, the feed can comprise a blend of a mineral oil feedstockwith a biocomponent feedstock. By “mineral oil” feedstock is meant afossil/mineral fuel source, such as crude oil, and not the commercialorganic product, such as sold under CAS number 8020-83-5, e.g., byAldrich. In the discussion below, a biocomponent feedstock refers to ahydrocarbon feedstock derived from a biological raw material component,from biocomponent sources such as vegetable, animal, fish, and/or algae.Generally, these biocomponent sources can include vegetable fats/oils,animal fats/oils, fish oils, pyrolysis oils, and algae lipids/oils, aswell as components of such materials, and in some embodiments canspecifically include one or more type of lipid compounds. Lipidcompounds are typically biological compounds that are insoluble inwater, but soluble in nonpolar (or fat) solvents. Non-limiting examplesof such solvents include alcohols, ethers, chloroform, alkyl acetates,benzene, and combinations thereof.

Major classes of lipids include, but are not necessarily limited to,fatty acids, glycerol-derived lipids (including fats, oils andphospholipids), sphingosine-derived lipids (including ceramides,cerebrosides, gangliosides, and sphingomyelins), steroids and theirderivatives, terpenes and their derivatives, fat-soluble vitamins,certain aromatic compounds, and long-chain alcohols and waxes.

In living organisms, lipids generally serve as the basis for cellmembranes and as a form of fuel storage. Lipids can also be foundconjugated with proteins or carbohydrates, such as in the form oflipoproteins and lipopolysaccharides.

Examples of vegetable oils that can be used in accordance with thisinvention include, but are not limited to rapeseed (canola) oil, soybeanoil, coconut oil, sunflower oil, palm oil, palm kernel oil, peanut oil,linseed oil, tall oil, corn oil, castor oil, jatropha oil, jojoba oil,olive oil, flaxseed oil, camelina oil, safflower oil, babassu oil,tallow oil and rice bran oil.

Vegetable oils as referred to herein can also include processedvegetable oil material. Non-limiting examples of processed vegetable oilmaterial include fatty acids and fatty acid alkyl esters. Alkyl esterstypically include C₁-C₅ alkyl esters. One or more of methyl, ethyl, andpropyl esters are preferred.

Examples of animal fats that can be used in accordance with theinvention include, but are not limited to, beef fat (tallow), hog fat(lard), turkey fat, fish fat/oil, and chicken fat. The animal fats canbe obtained from any suitable source including restaurants and meatproduction facilities.

Animal fats as referred to herein also include processed animal fatmaterial. Non-limiting examples of processed animal fat material includefatty acids and fatty acid alkyl esters. Alkyl esters typically includeC₁-C₅ alkyl esters. One or more of methyl, ethyl, and propyl esters arepreferred.

Algae oils or lipids are typically contained in algae in the form ofmembrane components, storage products, and metabolites. Certain algalstrains, particularly microalgae such as diatoms and cyanobacteria,contain proportionally high levels of lipids. Algal sources for thealgae oils can contain varying amounts, e.g., from 2 wt % to 40 wt % oflipids, based on total weight of the biomass itself Algal sources foralgae oils include, but are not limited to, unicellular andmulticellular algae. Examples of such algae include a rhodophyte,chlorophyte, heterokontophyte, tribophyte, glaucophyte,chlorarachniophyte, euglenoid, haptophyte, cryptomonad, dinoflagellum,phytoplankton, and the like, and combinations thereof. In oneembodiment, algae can be of the classes Chlorophyceae and/or Haptophyta.Specific species can include, but are not limited to, Neochlorisoleoabundans, Scenedesmus dimorphus, Euglena gracilis, Phaeodactylumtricornutum, Pleurochrysis carterae, Prymnesium parvum, Tetraselmischui, and Chlamydomonas reinhardtii. Additional or alternate algalsources can include one or more microalgae of the Achnanthes,Amphiprora, Amphora, Ankistrodesmus, Asteromonas, Boekelovia,Borodinella, Botryococcus, Bracteococcus, Chaetoceros, Carteria,Chlamydomonas, Chlorococcum, Chlorogonium, Chlorella, Chroomonas,Chrysosphaera, Cricosphaera, Crypthecodinium, Cryptomonas, Cyclotella,Dunaliella, Ellipsoidon, Eremosphaera, Ernodesmius, Euglena, Franceia,Fragilaria, Gloeothamnion, Haematococcus, Halocafeteria, Hymenomonas,Isochrysis, Lepocinclis, Micractinium, Monoraphidium, Nannochloris,Nannochloropsis, Navicula, Neochloris, Nephrochloris, Nephroselmis,Nitzschia, Ochromonas, Oedogonium, Oocystis, Ostreococcus, Pavlova,Parachlorella, Pascheria, Phaeodactylum, Phagus, Platymonas,Pleurochrysis, Pleurococcus, Prototheca, Pseudochlorella, Pyramimonas,Pyrobotrys, Scenedesmus, Skeletonema, Spyrogyra, Stichococcus,Tetraselmis, Thalassiosira, Viridiella, and Volvox species, and/or oneor more cyanobacteria of the Agmenellum, Anabaena, Anabaenopsis,Anacystis, Aphanizomenon, Arthrospira, Asterocapsa, Borzia, Calothrix,Chamaesiphon, Chlorogloeopsis, Chroococcidiopsis, Chroococcus,Crinalium, Cyanobacterium, Cyanobium, Cyanocystis, Cyanospira,Cyanothece, Cylindrospermopsis, Cylindrospermum, Dactylococcopsis,Dermocarpella, Fischerella, Fremyella, Geitleria, Geitlerinema,Gloeobacter, Gloeocapsa, Gloeothece, Halospirulina, Iyengariella,Leptolyngbya, Limnothrix, Lyngbya, Microcoleus, Microcystis,Myxosarcina, Nodularia, Nostoc, Nostochopsis, Oscillatoria, Phormidium,Planktothrix, Pleurocapsa, Prochlorococcus, Prochloron, Prochlorothrix,Pseudanabaena, Rivularia, Schizothrix, Scytonema, Spirulina, Stanieria,Starria, Stigonema, Symploca, Synechococcus, Synechocystis, Tolypothrix,Trichodesmium, Tychonema, and Xenococcus species.

The feedstock can include varying amounts of feedstreams based onbiocomponent sources. When desired, the feed can include at least about0.1 wt % of feed based on a biocomponent source, for example at leastabout 0.5 wt %, at least about 1 wt %, at least about 3 wt %, at leastabout 10 wt %, or at least about 15 wt %. In such embodiments, the feedcan include about 60 wt % or less of biocomponent, for example about 50wt % or less, about 40 wt % or less, or about 30 wt % or less. In otherembodiments, the amount of biocomponent feed (e.g., for co-processingwith the mineral oil portion of the feed) can be relatively small, forinstance with a feed that includes at least about 0.5 wt % of feedstockbased on a biocomponent source, e.g., at least about 1 wt %, at leastabout 2.5 wt %, or at least about 5 wt %. In such embodiments, the feedcan include about 20 wt % or less of biocomponent based feedstock, forexample about 15 wt % or less, about 10 wt % or less, or about 5 wt % orless.

The biocomponent feeds usable in the present invention can include anyof those which comprise primarily triglycerides and free fatty acids(FFAs). The triglycerides and FFAs typically contain aliphatichydrocarbon chains in their structure having from 8 to 36 carbons,preferably from 10 to 26 carbons, for example from 14 to 22 carbons.Types of triglycerides can be determined according to their fatty acidconstituents. The fatty acid constituents can be readily determinedusing Gas Chromatography (GC) analysis. This analysis involvesextracting the fat or oil, saponifying (hydrolyzing) the fat or oil,preparing an alkyl (e.g., methyl) ester of the saponified fat or oil,and determining the type of (methyl) ester using GC analysis. In oneembodiment, a majority (i.e., greater than 50%) of the triglyceridepresent in the lipid material can be comprised of C₁₀ to C₂₆ fatty acidconstituents, based on total triglyceride present in the lipid material.Further, a triglyceride is a molecule having a structure identical tothe reaction product of glycerol and three fatty acids. Thus, although atriglyceride is described herein as being comprised of fatty acids, itshould be understood that the fatty acid component does not necessarilycontain a carboxylic acid hydrogen. In one embodiment, a majority oftriglycerides present in the biocomponent feed can preferably becomprised of C₁₂ to C₁₈ fatty acid constituents, based on totaltriglyceride content. Other types of feed that are derived frombiological raw material components can include fatty acid esters, suchas fatty acid alkyl esters (e.g., FAME and/or FAEE).

Biocomponent based diesel boiling range feedstreams typically haverelatively low nitrogen and sulfur contents. For example, a biocomponentbased feedstream can contain up to about 300 wppm nitrogen, for exampleup to about 100 wppm nitrogen. Instead of nitrogen and/or sulfur, theprimary heteroatom component in biocomponent feeds is oxygen.Biocomponent diesel boiling range feedstreams, e.g., can include as muchas about 10-12 wt % oxygen.

Supported Catalyst

Supported catalysts useful in various embodiments can be selected fromconventional hydrotreating catalysts, such as a catalyst composed of aGroup VIB metal and/or a Group VIII metal on a support. Suitable metalscan include, but are not limited to, cobalt, iron, nickel, molybdenum,tungsten, and combinations thereof. In some preferred embodiments, themetals can include nickel and molybdenum or nickel, cobalt, andmolybdenum. The total metals content on the supported catalyst can rangefrom about 5 wt % to about 40 wt %, relative to the total weight of thecatalyst. The support can be any suitable refractory support material,such as silica, alumina, silica-alumina, titania, zirconia, or the like,or a combination thereof.

Bulk Catalyst Composition

In certain embodiments, improved hydroprocessing can be achieved byincluding a bulk metal catalyst in at least one stage of ahydrotreatment process, e.g., for treating high nitrogen feeds. Acatalyst composition comprising bulk catalyst particles can includeabout 30 wt % to about 100 wt % (preferably from about 40 wt % to about99.9 wt %, for example from about 50 wt % to about 99.5 wt %, from about60 wt % to about 99 wt %, from about 80 wt % to about 99.9 wt %, or fromabout 85 wt % to about 99.9 wt %) of at least one Group VIII(particularly non-noble) metal and at least one Group VIB metal, basedon the total weight of the bulk catalyst particles, calculated as metaloxides.

Techniques for producing bulk metal catalyst particles are known andhave been previously described, for example in U.S. Pat. No. 6,162,350,which is hereby incorporated by reference. Bulk metal catalyst particlescan be made via methods where all of the metal catalyst precursors arein solution, or via methods where at least one of the precursors is inat least partly in solid form, optionally but preferably while at leastanother one of the precursors is provided only in a solution form.Providing a metal precursor at least partly in solid form can beachieved, for example, by providing a solution of the metal precursorthat also includes solid and/or precipitated metal in the solution, suchas in the form of suspended particles. Examples 2-4 below provideexamples of using both a “solution” method and a “solid” method forcreating bulk catalyst particles according to the invention.

Catalyst compositions comprising bulk catalyst particles comprising oneGroup VIII non-noble metal and two Group VIB metals can be preferred.Group references herein are made to the CAS version of the PeriodicTable of Elements. It has been found that, in such cases, the bulkcatalyst particles can be sintering-resistant. Thus, the active surfacearea of the bulk catalyst particles can be significantly maintainedduring use. The molar ratio of Group VIB to Group VIII non-noble metalscan range generally from about 10:1 to about 1:10, preferably from about3:1 to about 1:3. In some embodiments, a bulk catalyst particle may havea “core-shell” structure, where a catalyst particle is formed with ametal shell having a composition according the invention around a coreof one the constituent metals. In the case of a core-shell structuredparticle, the above ratios can apply to the metals contained in theshell. If more than one Group VIB metal is contained in the bulkcatalyst particles, the ratio of the different Group VIB metals isgenerally not critical. The same holds when more than one Group VIIInon-noble metal is applied. In the case where molybdenum and tungstenare present as Group VIB metals, the molybdenum:tungsten ratio canpreferably be in the range from about 9:1 to about 1:9. Preferably, theGroup VIII non-noble metal can comprise nickel and/or cobalt.Additionally or alternately, the Group VIB metal can comprise molybdenumand/or tungsten, preferably a combination of molybdenum and tungsten. Invarious preferred embodiments, combinations of Ni/Mo/W, Co/Mo/W, orNi/Mo/Co/W can be used. These types of precipitates appear to besinter-resistant. Thus, the active surface area of the precipitate canadvantageously be retained during use. The metals can preferably bepresent as oxidic compounds of the corresponding metals, or, if thecatalyst composition has been sulfided, as sulfidic compounds of thecorresponding metals.

Preferably, the bulk metal particles can have a surface area of at leastabout 50 m²/g, for example at least about 100 m²/g, as measured via theB.E.T. method. It may further be preferred that the particles cancomprise (or can consist essentially of) from about 50 wt % to about 100wt %, for example from about 70 wt % to about 100 wt %, of at least oneGroup VIII non-noble metal and at least one Group VIB metal, based onthe total weight of the particles, calculated as metal oxides. Theamount of Group VIB and Group VIII non-noble metals can easily bedetermined, e.g., via TFM-EDX. For the purposes of the aboveembodiments, the term “consisting essentially of” is used to refer tocatalysts that include the identified transition metals, but excludeother transition metals. Although the catalyst particles mentionedherein are disclosed to contain certain transition metals (e.g., inoxide form, or after the oxide form has been sulfidized underappropriate sulfidization conditions), optionally on a support, the(non-support) remainder of the catalyst particles may additionally oralternately contain additional components, such as other transitionmetals (e.g., rhenium, ruthenium, rhodium, iridium, chromium, vanadium,iron, cobalt, platinum, palladium, cobalt, nickel, molybdenum, tungsten,or combinations thereof), rare earth metals, organic ligands (e.g., asadded or as precursors left over from oxidation and/or sulfidizationsteps), phosphorus compounds, boron compounds, fluorine-containingcompounds, silicon-containing compounds, promoters, binders, fillers, orlike agents, or combinations thereof. All these transition and/or rareearth metals can generally be present in an oxidic form if the catalystcomposition has been calcined and/or in a sulfided form if the catalystcomposition has been sulfided.

In embodiments where the catalyst composition includes a bindermaterial, such binder material can include silica, silica-alumina (suchas conventional silica-alumina, silica-coated alumina and alumina-coatedsilica), alumina (such as (pseudo)boehmite or gibbsite), titania,zirconia, cationic clays or anionic clays (such as saponite, bentonite,kaoline, sepiolite, or hydrotalcite), or mixtures thereof. The particlescan be embedded in the binder material, which can function as a “glue”to hold the particles together. Preferably, the particles can besubstantially homogeneously distributed within the binder. The presenceof the binder can thus generally lead to an increased mechanicalstrength and/or resiliency of the final catalyst composition. Generally,the catalyst composition of the invention can exhibit a mechanicalstrength, expressed as side crush strength, of at least about 1 lb/mm(about 4.4 N/mm), for example at least about 3 lb/mm (about 13 N/mm),measured on extrudates with a diameter of about 1 mm to about 2 mm Thebinder material can generally contain about 0 wt % to about 90 wt %(based only on the weight of the binder material) of the Group VIBand/or Group VIII (non-noble) metals that are also contained in the bulkcatalyst particles.

The amount of binder can depend on the desired activity of the catalystcomposition and can be from about 0 wt % to about 95 wt % of the totalcomposition, depending on the envisaged catalytic application. However,to take advantage of the unusual high activity of the bulk catalysts ofthe present invention, binder amounts, when present, can generally be inthe range from about 0.1 wt % to about 70 wt % of the total composition,preferably from about 0.1 wt % to about 60 wt %, for example from about0.1 wt % to about 20 wt %, from about 0.1 wt % to about 15 wt %, fromabout 0.1 wt % to about 10 wt %, from about 0.5 wt % to about 50 wt %,from about 0.5 wt % to about 20 wt %, from about 0.5 wt % to about 15 wt%, or from about 0.5 wt % to about 10 wt %.

In an embodiment, the pore size distribution of the particles can beapproximately the same as for conventional hydrotreating catalysts. Forexample, the particles can have a pore volume from about 0.05 mL/g toabout 5 mL/g, for example from about 0.1 mL/g to about 4 mL/g, fromabout 0.1 mL/g to about 3 mL/g, or from about 0.1 mL/g to about 2 mL/g,as determined by nitrogen adsorption methods. It can be preferred thatpores smaller than about 1 nm are substantially not present. Theparticles can have a median diameter of at least about 50 μm, forexample at least about 100 μm, and/or not more than about 5000 μm, forexample not more than about 3000 μm. In a preferred embodiment, themedian particle diameter can be from about 250 μm to about 2500 μm, forexample from about 500 μm to about 2000 μm.

The bulk catalyst particles can have a characteristic X-ray diffractionpattern that can differ from conventional hydroprocessing catalystsobtained by impregnation or co-mixing. The X-ray diffraction pattern ofthe bulk catalyst particles can comprise, and can preferably consistessentially of, peaks characteristic to the reacted metal components.For example, a nickel hydroxy-carbonate component contacted with amolybdenum and tungsten component can result in bulk catalyst particlescharacterized by an X-ray diffraction (XRD) pattern comprising peaksexhibiting approximate d values of: (4.09), 2.83, 2.54, 2.32, 2.23,1.71, (1.54), 1.47. Values in brackets indicate that the correspondingpeaks can be rather broad, can have a relatively low intensity, and/orare not readily distinguishable. The phrase “consist essentially of”,with reference to the aforementioned XRD pattern, should be understoodto mean that, apart from the explicitly recited peaks, there aresubstantially no further peaks contained in the diffraction pattern. Theprecipitate for catalyst obtained by the solution route can have acharacteristic XRD pattern that differs from catalyst obtained byco-mixing and conventional hydroprocessing catalysts obtained byimpregnation. For instance the XRD pattern of a Ni/Mo/W precipitate, asprepared by the solution route, can exhibit peaks at approximate dvalues of: 2.52, 1.72, and 1.46.

In another embodiment, the bulk catalyst particles obtained can becharacterized by an XRD pattern that contains virtually no peakcorresponding to any of the metal components applied in this process asstarting materials. Of course, if desired, it can also be possible tochoose the amounts of metal components in such a way as to obtain bulkcatalyst particles characterized by an XRD pattern still comprising oneor more peaks characteristic to at least one of these metal components.If, e.g., a high amount of the metal component which is at least partlyin the solid state during contacting is added, or if this metalcomponent is added in the form of relatively large particles, smallamounts of this metal component may be traced in the XRD pattern of theresulting bulk catalyst particles.

Generally, if the solid route is applied, at least one of the metals canbe anisotropically distributed in the particles. The metal of the metalcomponent at least partly in the solid state during the solid route cangenerally be concentrated in the inner part, i.e., the core, of thefinal particles. Generally, the concentration of this metal in the outerpart, i.e., the shell, of the final particles can be at most about 95%,and in most cases at most about 90%, of the concentration of this metalin the core of the final particles. Further, it has been found that themetal of a metal component applied in the solute state during the solidroute may also be anisotropically distributed in the particles. In suchsituations, the concentration of this metal in the core of the particlescan particularly be lower than the concentration of this metal in theshell. For instance, the concentration of this metal in the core of theparticles can be at most about 80%, in some embodiments at most about65% or at most about 50%, of the concentration of this metal in theshell. It must be noted that the above-described anisotropic metaldistributions may be found in the composition of the invention,independently of whether the composition has been calcined and/orsulfided or not.

In the above cases, the shell can generally have a thickness from about50 nm to about 1000 nm, preferably from about 100 nm to about 500 nm.The amount of these particles in the catalyst composition of theinvention can preferably be from about 5 wt % to about 100 wt %, basedon the total weight of the catalyst composition.

The surface area of the catalyst composition can preferably be at leastabout 40 m²/g, for example at least about 80 m²/g or at least about 120m²/g. The total pore volume of the catalyst composition can preferablybe at least about 0.05 mL/g, for example at least about 0.1 mL/g, asdetermined by water porosimetry. To obtain catalyst compositions withrelatively high mechanical strength, it may be desirable for thecatalyst composition of the invention to have a relatively lowmacroporosity.

In a preferred embodiment, the catalyst composition can comprise a bulkmixed metal oxide (preferably sulfided prior to use), which can berepresented by the formula (Ni)_(b)(Mo)_(c)(W)_(d)O_(z), wherein themolar ratio of b:(c+d) can be from about 0.5:1 to about 3:1, preferablyfrom about 0.75:1 to about 1.5:1, for example from about 0.75:1 to about1.25:1. The molar ratio of c:d can preferably be greater than about0.01:1, preferably greater than about 0.1:1, for example from about 1:10to about 10:1, from about 1:3 to about 3:1, or corresponding tosubstantially equimolar amounts of Mo and W (e.g., between about 2:3 andabout 3:2). Given the preferred valences of nickel being 2 and Mo and Wbeing 6, the amount of oxygen can preferably be z=[2b+6(c+d)]/2. In suchan embodiment, the catalyst composition can comprise or can consistessentially of a substantially amorphous material having a unique XRDpattern, showing crystalline peaks at d≈2.53 Å and 1.70 Å.

Process Conditions

In various embodiments, the reaction conditions can be selected to beeffective hydrotreatment conditions. One possible type of effectivehydrotreatment conditions can be conditions suitable for hydrotreatmentof a feed prior to fluid catalytic cracking. A bulk metal hydrotreatingcatalyst can be included as at least a portion of the hydrotreatingcatalyst used for the hydrotreatment process. For example, in ahydrotreatment process involving multiple beds of hydrotreatingcatalyst, at least a portion of one bed can comprise a bulk metalcatalyst. The amount of bulk metal hydrotreating catalyst can correspondto at least about 10% of a bed, for example at least about 25% of a bed,at least about 50% of a bed, at least one entire bed, or at leastmultiple entire beds within a hydrotreatment reaction system. The bulkmetal hydrotreating catalyst can be included at any convenient locationwithin the hydrotreating reactors, stages, and/or beds, preferablytoward the downstream end of the hydrotreatment process, for example inat least about the latter half of the catalyst to which a feedstock isexposed.

The reaction conditions can include an LHSV from about 0.1 hr⁻¹ to about2.0 hr⁻¹, a total pressure from about 800 psig (about 5.5 MPag) to about3000 psig (about 20.7 MPag), a treat gas rate of at least about 1000scf/b (about 170 Nm³/m³), for example at least about 2000 scf/b (about340 Nm³/m³) of at least about 80% hydrogen (e.g., remainder inert gas),and a temperature from about 600° F. (about 316° C.) to about 800° F.(about 427° C.). In one preferred embodiment, the reaction conditionscan include an LHSV from about 0.5 hr⁻¹ to about 1.5 hi', a totalpressure from about 1400 psig (about 9.7 MPag) to about 2000 psig (about13.8 MPag), a hydrogen treat gas rate from about 2000 scf/b (about 340Nm³/m³) to about 5000 scf/b (about 840 m³/m³) of at least about 80%hydrogen (e.g., remainder inert gas), and a temperature from about 650°F. (about 343° C.) to about 750° F. (about 399° C.). Additionally oralternately, the hydrogen treat gas rate can be from about 2500 scf/b(about 420 Nm³/m³) to about 4000 scf/b (about 670 Nm³/m³) of at leastabout 90% hydrogen (e.g., remainder inert gas).

The hydrotreatment can be performed by exposing a feed to a catalyst inone or more reactors and/or stages, with each reactor and/or stagepossibly including one or more catalyst beds. Optionally, one or moreintermediate separations and/or quenches may be included betweensuccessive reactors, stages, or beds during the hydrotreatment.Intermediate separations could be used, for example, to reduce theconcentration of H₂S and/or NH₃ generated in the reaction system duringthe hydrotreatment. Intermediate quenches can be used, for example, tocontrol reaction temperatures that may rise, due to the exothermicnature of many reactions occurring during hydrotreatment.

After hydrotreatment and to the extent necessary, the hydrotreated feedcan be passed to a separator/fractionator for removal of gas phaseproducts, such as H₂S, CO, CO₂, and/or NH₃. The fractionation canoptionally also produce a diesel boiling range fraction and a heavierfraction such as a gas oil fraction. After removal of the gas phaseproducts, the hydrotreated feed (or at least the heavier fraction) canbe sent to a fluid catalytic cracking unit, e.g., for production of anaphtha product.

Reaction Products

In various embodiments, process conditions can be selected toeffectively hydrotreat a relatively high nitrogen content feedstock.Conditions can be selected to achieve one or more desired productcharacteristics. For example, the hydrotreating conditions can beselected to achieve a sulfur content of about 1000 wppm or less, forexample about 500 wppm or less, about 350 wppm or less, or about 250wppm or less. Additionally or alternately, the sulfur content can bereduced to about 100 wppm or more, for example about 200 wppm or more orabout 500 wppm or more. These sulfur levels can allow the hydrotreatedeffluent to be used as an input for a fluid catalytic cracking process.

In addition or alternately to the sulfur content, the hydrotreatingconditions can be selected to achieve a nitrogen level of about 1200wppm or less, for example about 1000 wppm or less, about 900 wppm orless, about 750 wppm or less, or about 500 wppm or less. Additionally oralternately, the nitrogen content can be reduced to about 100 wppm ormore, for example about 200 wppm or more or about 500 wppm or more.

In addition or alternately to the sulfur and/or nitrogen content, thehydrotreating conditions can be selected to achieve an improved amountof aromatics saturation in a hydrotreated effluent, e.g., to produce ahydrotreated effluent having an API gravity of greater than about 25.Additionally or alternately, the hydrotreating conditions can beselected to produce a hydrotreated effluent having an API gravity thatgreater than the API gravity of the feedstock, for example at leastabout 1 greater, at least about 3 greater, or at least about 5 greater.

Additional Embodiments

In an alternate embodiment, the present invention can relate to a methodfor effectively utilizing heteroatom removal capability of a bulkcatalyst in removing heteroatoms from a hydrocarbon feedstock, themethod comprising: hydrotreating a first hydrocarbon feedstock bycontacting the first feedstock with a bulk catalyst containing at leastthree of the following metals: cobalt, nickel, molybdenum, and tungsten(e.g., nickel, molybdenum, and tungsten, as detailed hereinabove), saidbulk catalyst in its unused state having a relative volumetric catalyticactivity for hydrodesulfurization and/or hydrodenitrogenation, with thecontacting being done under conditions effective to at least partiallyhydrodesulfurize and/or hydrodenitrogenate the first feedstock, whereinthe contacting continues until the bulk catalyst exhibits a relativevolumetric hydrodesulfurization activity of not more than 60% (forexample not more than 55% or not more than 50%) of the relativevolumetric hydrodesulfurization activity in its unused state; isolatingthe hydrotreated first hydrocarbon feedstock; hydrotreating a secondhydrocarbon feedstock by contacting the second feedstock with the bulkcatalyst whose relative volumetric hydrodesulfurization activity is notmore than 60% (for example not more than 55% or not more than 50%) ofthe relative volumetric hydrodesulfurization activity in its unusedstate, with the contacting being done under conditions effective to atleast partially hydrodesulfurize and/or hydrodenitrogenate the secondfeedstock, as well as to hydrodeoxygenate the second feedstock; andisolating the hydrotreated second hydrocarbon feedstock. Advantageously,in this embodiment, one or more of the to following can be satisfied:the second hydrocarbon feedstock can contain at least 10 wt % (forexample at least 15 wt % or at least 20 wt %) more biocomponent contentthan the first hydrocarbon feedstock; the first hydrocarbon feedstockhas a pre-treated sulfur content, the hydrotreated first hydrocarbonfeedstock has a post-treated sulfur content, and the post-treated sulfurcontent can be no more than 3.0% (e.g., no more than 2.0%, no more than1.0%, or no more than 0.5%) of the pre-treated sulfur content; thesecond hydrocarbon feedstock has a pre-treated oxygen content and apre-treated sulfur content, the hydrotreated second hydrocarbonfeedstock has a post-treated oxygen content and a post-treated sulfurcontent, the post-treated oxygen content can be no more than 1.0% (e.g.,no more than 0.5%, no more than 0.3%, or no more than 0.1%) of thepre-treated oxygen content and/or the pre-treated sulfur content can beno more than 3.0% (e.g., no more than 2.0%, no more than 1.0%, or nomore than 0.5%) of the post-treated sulfur content; and the isolatedhydrotreated second hydrocarbon feedstock can both be combined with eachother and/or with a fuel pool (e.g., a diesel fuel pool).

Additionally or alternately in such embodiment(s), one or more of thefollowing can be satisfied: the first hydrocarbon feedstock can have asulfur content of at least 500 wppm and can be comprised of from 80 wt %to 100 wt % of a diesel boiling range mineral feedstock and from 0 wt %to 20 wt % of a diesel boiling range biocomponent feedstock; the secondhydrocarbon feedstock can have a sulfur content of at least 500 wppmand/or an oxygen content of at least 1 wt % and can be comprised of from10 wt % to 80 wt % of a diesel boiling range mineral feedstock and from20 wt % to 90 wt % of a diesel boiling range biocomponent feedstock; andthe contacting in the first hydrotreatment step can continue until thebulk catalyst exhibits a relative volumetric hydrodesulfurizationactivity of not more than 50% of the relative volumetrichydrodesulfurization activity in its unused state.

Further additionally or alternately, the present invention includes oneor more of the following embodiments.

Embodiment 1

A process for hydrotreating a feedstock having a high nitrogen content,comprising: (a) contacting a hydrocarbon feedstock having a nitrogencontent of at least about 3000 wppm with a supported hydrotreatingcatalyst under first hydrotreating conditions; and (b) contacting thehydrotreated hydrocarbon feedstock with a sulfided bulk metal catalystunder second hydrotreating conditions to produce a hydrotreatedeffluent, said catalyst comprising a non-noble Group VIII metalmolybdate in which at least a portion, but less than all, of themolybdenum has been replaced by tungsten, wherein the bulk metalcatalyst, prior to sulfidation, is represented by the formula:(X)_(b)(Mo)_(c)(W)_(d)O_(z), wherein X is a non-noble Group VIII metal,the molar ratio of b:(c+d) is from about 0.5:1 to about 3:1, the molarratio of c:d is greater than about 0.01:1, and z=[2b+6(c+d)]/2.

Embodiment 2

A process for hydrotreating a feedstock having a high nitrogen content,comprising: (a) contacting a hydrocarbon feedstock having a nitrogencontent of at least about 3000 wppm with a supported hydrotreatingcatalyst under first hydrotreating conditions; (b) contacting thehydrotreated hydrocarbon feedstock with a sulfided bulk metal catalystunder second hydrotreating conditions to produce a twice hydrotreatedfeedstock, said catalyst comprising a non-noble Group VIII metalmolybdate in which at least a portion, but less than all, of themolybdenum has been replaced by tungsten, wherein the bulk metalcatalyst, prior to sulfidation, is represented by the formula:(X)_(b)(Mo)_(c)(W)_(d)O_(z), wherein X is a non-noble Group VIII metal,the molar ratio of b:(c+d) is from about 0.5:1 to about 3:1, the molarratio of c:d is greater than about 0.01:1, and z=[2b+6(c+d)]/2; (c)contacting the twice hydrotreated feedstock with a supportedhydrotreating catalyst under third hydrotreating conditions to produceat least a thrice hydrotreated effluent; and (d) delivering the thricehydrotreated effluent to a fluid catalytic cracking stage.

Embodiment 3

The process of embodiment 1 or embodiment 2, wherein the hydrocarbonfeedstock has an API gravity of at least about 20.

Embodiment 4

The process of any one of the previous embodiments, wherein thehydrocarbon feedstock has a T10 boiling point of at least about 300° F.(about 149° C.).

Embodiment 5

The process of any one of the previous embodiments, wherein thehydrotreated effluent has an API gravity greater than an API gravity ofthe hydrocarbon feedstock, and preferably wherein the hydrotreatedeffluent has an API gravity greater than about 25.

Embodiment 6

The process of any one of the previous embodiments, wherein the molarratio of b:(c+d) is from about 0.75:1 to about 1.25:1.

Embodiment 7

The process of any one of the previous embodiments, wherein the molarratio of c:d is from about 1:10 to 10:1.

Embodiment 8

The process of any one of the previous embodiments, wherein thehydrocarbon feedstock has a nitrogen content of at least about 4000wppm.

Embodiment 9

The process of any one of the previous embodiments, wherein at least oneof the first hydrotreating conditions, the second hydrotreatingconditions, and the third hydrotreating conditions include an LHSV fromabout 0.1 hr⁻¹ to about 2.0 hr⁻¹, a total pressure from about 800 psig(about 5.5 MPag) to about 3000 psig (about 20.7 MPag), a treat gas rateof at least about 1000 scf/b (about 170 Nm³/m³) using at least 80%hydrogen, and a temperature from about 600° F. (about 316° C.) to about800° F. (about 427° C.).

Embodiment 10

The process of any one of the previous embodiments, wherein at least oneof the first hydrotreating conditions, the second hydrotreatingconditions, and the third hydrotreating conditions include an LHSV fromabout 0.5 hr⁻¹ to about 1.5 hr⁻¹, a total pressure from about 1400 psig(about 9.7 MPag) to about 2000 psig (about 13.8 MPag), a hydrogen treatgas rate from about 2000 scf/b (about 340 Nm³/m³) to about 5000 scf/b(about 840 Nm³/m³) using at least 80% hydrogen, and a temperature fromabout 650° F. (about 343° C.) to about 750° F. (about 399° C.).

Embodiment 11

The process of any one of the previous embodiments, wherein X comprisesNi or Co, preferably wherein X is Ni.

Embodiment 12. A method for effectively utilizing heteroatom removalcapability of a bulk catalyst in removing heteroatoms from a hydrocarbonfeedstock, the method comprising: hydrotreating a first hydrocarbonfeedstock by contacting the first feedstock with a bulk catalystcontaining at least three of the following metals: cobalt, nickel,molybdenum, and tungsten (e.g., nickel, molybdenum, and tungsten), saidbulk catalyst in its unused state having a relative volumetric catalyticactivity for hydrodesulfurization and/or hydrodenitrogenation, with thecontacting being done under conditions effective to at least partiallyhydrodesulfurize and/or hydrodenitrogenate the first feedstock, whereinthe contacting continues until the bulk catalyst exhibits a relativevolumetric hydrodesulfurization activity of not more than 60% (forexample not more than 55% or not more than 50%) of the relativevolumetric hydrodesulfurization activity in its unused (fresh) state;isolating the hydrotreated first hydrocarbon feedstock; hydrotreating asecond hydrocarbon feedstock by contacting the second feedstock with thebulk catalyst whose relative volumetric hydrodesulfurization activity isnot more than 60% (for example not more than 55% or not more than 50%)of the relative volumetric hydrodesulfurization activity in its unusedstate, with the contacting being done under conditions effective to atleast partially hydrodesulfurize and/or hydrodenitrogenate the secondfeedstock, as well as to hydrodeoxygenate the second feedstock; andisolating the hydrotreated second hydrocarbon feedstock, wherein: thesecond hydrocarbon feedstock contains at least 10 wt % (for example atleast 15 wt % or at least 20 wt %) more biocomponent content than thefirst hydrocarbon feedstock; the first hydrocarbon feedstock has apre-treated sulfur content, the hydrotreated first hydrocarbon feedstockhas a post-treated sulfur content, and the post-treated sulfur contentis no more than 3.0% (e.g., no more than 2.0%, no more than 1.0%, or nomore than 0.5%) of the pre-treated sulfur content; the secondhydrocarbon feedstock has a pre-treated oxygen content and a pre-treatedsulfur content, the hydrotreated second hydrocarbon feedstock has apost-treated oxygen content and a post-treated sulfur content, thepost-treated oxygen content is no more than 1.0% (e.g., no more than0.5%, no more than 0.3%, or no more than 0.1%) of the pre-treated oxygencontent, and the pre-treated sulfur content is no more than 3.0% (e.g.,no more than 2.0%, no more than 1.0%, or no more than 0.5%) of thepost-treated sulfur content; and the isolated hydrotreated firsthydrocarbon feedstock and the isolated hydrotreated second hydrocarbonfeedstock are both combined with a fuel pool (e.g., a diesel fuel pool).

Embodiment 13

The method of embodiment 12, wherein the first hydrocarbon feedstock hasa sulfur content of at least 500 wppm and is comprised of from 80 wt %to 100 wt % of a diesel boiling range mineral feedstock and from 0 wt %to 20 wt % of a diesel boiling range biocomponent feedstock; wherein thesecond hydrocarbon feedstock has a sulfur content of at least 500 wppmand an oxygen content of at least 1 wt % and is comprised of from 10 wt% to 80 wt % of a diesel boiling range mineral feedstock and from 20 wt% to 90 wt % of a diesel boiling range biocomponent feedstock; andwherein the contacting in the first hydrotreatment step continues untilthe bulk catalyst exhibits a relative volumetric hydrodesulfurizationactivity of not more than 50% of the relative volumetrichydrodesulfurization activity in its unused state.

EXAMPLES

This invention is illustrated in greater detail by the specific examplespresented below. It is understood that these examples are to beconsidered as specific examples or embodiments of the overall aspect ofthe invention as claimed.

Example 1 Reaction System

A reaction system suitable for carrying out the above processes is shownschematically in FIG. 1. In FIG. 1, two hydrotreatment reactors 105 and125 are pictured. Reactor 105 can include beds 111, 112, and 113, whilereactor 106 can include beds 131, 132, and 133. In other embodiments,any convenient numbers of reactors can be used to have any convenientnumber of stages that include any convenient number of beds. As analternative example, another option would be to have two reactors, withtwo beds in a first reactor and four beds in a second reactor.

In FIG. 1, bed 111 can be used as a guard bed, including catalystssuitable for demetallization and/or other removal of heavy metalcontaminants such as arsenic. Examples of suitable guard bed catalystscan include, but are not limited to, catalyst particles composedsubstantially of a refractory material, such as alumina, and/orrelatively low activity particles such as a low activity nickel catalystsupported on alumina Other suitable demetallization and/or guard bedcatalysts are conventionally known.

In FIG. 1, beds 112 and 113 can include a hydrotreatment catalyst, suchas a catalyst including a Group VIB and a Group VIII metal supported ona refractory support. All of the beds in reactor 105 can be operatedunder effective hydrotreating conditions.

A feed 102 can be passed into reactor 105, along with a hydrogen stream103. The feed 102 can be hydrotreated by exposing the feed to thecatalysts in beds 111, 112, and 113. The effluent 108 from reactor 105can be passed to an intermediate separator 115. Intermediate separator115 can allow for removal by separation of gas phase contaminants 116(such as H₂S, CO, CO₂, and/or NH₃) that may be produced during thereactions occurring in reactor 105. Additionally or alternately, aseparator can be included at any other convenient location in thereaction system including between any beds, stages, or reactors asdesired.

The liquid phase product 118 from separator 115 can then be passed toreactor 125. Beds 131 and 133 in reactor 125 can include supportedhydrotreating catalyst. Bed 132 can includes a portion of supportedhydrotreating catalyst and a portion of bulk metal catalyst. All of thebeds in reactor 125 can be operated under effective hydrotreatingconditions. An optional quench gas stream 137 can be introduced intoreactor 125 at a convenient location, such as between beds 131 and 132.The quench gas stream 137 can be any convenient gas for controllingtemperature within the reaction system. Preferably, quench gas stream137 can be a hydrogen containing stream. Additionally or alternately, anoptional quench gas stream at any other convenient location and/or morethan one quench gas stream can be used.

The effluent 128 from the second reactor 125 can then be passed to afractionator or separator 145. If the entire liquid effluent from secondreactor 125 is used as a feed for another reaction, such as a fluidcatalytic cracking reaction, then a separator can be used just to removecontaminant gases and non-condensable hydrocarbons 151. Alternately, afractionator 145 can be used to produce at least two products, such as adiesel boiling range product 152 and a higher boiling product 154. Thehigher boiling product can be used as an input for a fluid catalyticcracking process, and/or the diesel boiling range product can be blendedwith other diesel streams and/or undergo further processing for eventualinclusion in the diesel fuel pool. In other embodiments, any otherconvenient cut point can be used to create two or more desired streamsfrom a fractionator 145.

Example 2 Preparation of NiMo_(0.5)W_(0.5)O₄ by Boiling Decomposition

In a 1-liter flask, about 13.2 grams of ammonium molybdate (about 0.075moles Mo), about 18.7 grams of ammonium metatungstate (about 0.075 molesW), and about 43.6 grams of nickel nitrate hexahydrate (about 0.15 molesNi) were dissolved in approximately 300 mL of water, so that theresulting pH was about 4.3. To this solution, a concentrated NH₄OHsolution (about 600 mL) was added until the pH reached about 10. At thispoint, some precipitate remained. The solution was refluxed at about100° C. for about 3 hours, during which heating the precipitatedissolved to give a clear blue solution, and, upon further heating, agreen precipitate formed. The heating was continued until the pH wasbetween about 6.8 and about 7. The suspension was then cooled to roomtemperature (about 20-25° C.), filtered, washed with water, and dried atapproximately 120° C. overnight (about 12-16 hours). About 18 grams ofmaterial was obtained, with the XRD spectrum showing an amorphousbackground with the two largest peaks being at d≈2.58 Å and 1.70 Å.

Example 3 Preparation of NiMo_(0.5)W_(0.5)O₄ by Direct Precipitation

In a 1-liter flask, about 17.65 grams of ammonium molybdate (about 0.1mole Mo) and about 24.60 grams of ammonium metatungstate (about 0.1 moleW) were dissolved in about 800 mL of water, giving a solution pH ofabout 5.2. To this solution, about 0.4 moles of NH₃ (about 30 mL) wasadded, raising the pH to about 9.8 (solution A). This solution waswarmed to about 90° C. A second solution was prepared by adding about58.2 grams of nickel nitrate (about 0.2 moles Ni), which was dissolvedin approximately 50 mL of water (solution B), and was maintained at atemperature of about 90° C. This solution was added dropwise at a rateof about 7 mL/min into the ammonium molybdate/ammonium metatungstatesolution. A precipitate began to form after about ¼ of the solution wasadded. This suspension, which was at a pH about 6.5, was stirred forabout 30 minutes, while the temperature was maintained at about 90° C.The material was filtered hot, washed with hot water, and dried at about120° C. Approximately 38 grams of material was recovered.

Example 4 Preparation of NiMo_(0.5)W_(0.5)O₄ by Controlled pHPrecipitation

Two solutions were prepared with approximately the same amounts ofnickel, tungsten, molybdenum, and ammonia (ammonium hydroxide) asdescribed in Example 3 (solutions A and B), except that each solutioncontained about 700 mL of water. The two solutions were added into aseparate vessel initially containing about 400 mL of water held at about90° C. Solution B (the acidic solution) was pumped into the vessel at aconstant rate of about 15 mL/min, while solution A was added through aseparate pump under feedback PC control, which was set to maintain thepH at about 6.5. On mixing the two solutions, a precipitate formed. Theslurry was stirred at about 90° C. for about 30 minutes, filtered hot,washed with hot water, and dried at about 120° C.

Example 5 Working and Comparative Example of Hydrotreatment Processes

Four reactors were each loaded with hydrotreating catalyst. Reactors 1and 2 were loaded with 100% of a conventional supported NiMohydrotreating catalyst. Reactor 3 was loaded with about 75% of theconventional supported NiMo hydrotreating catalyst on top of about 25%of a bulk metal hydrotreating catalyst according to the invention (inother words, the bulk metal catalyst was in the downstream ˜25% of thereactor). In Reactor 3, the bulk metal hydrotreating catalyst was aNiMo_(0.5)W_(0.5)O₄ version of the bulk catalyst. The fourth reactor wasloaded with about 50% of the conventional supported NiMo hydrotreatingcatalyst on top of about 50% of the NiMo_(0.5)W_(0.5)O₄ version of thebulk metal hydrotreating catalyst.

The catalyst in Reactor 1 was sulfided via a gas phase sulfidationprocedure using about 3% H₂S/H₂. For reactors 2-4, the sulfidation wasperformed as a liquid phase sulfidation using the 3% H₂S/H₂ along with afeed primarily composed of a feed that was previously hydrotreated to asufficient degree to be suitable for use in an FCC process. Each reactorwas then conditioned for about three days by running a virgin vacuum gasoil feed through each reactor under the hydrotreating conditionsdescribed below.

For the hydrotreatment examples, a feed was used that was a combinationof a virgin vacuum gas oil and a product gas oil stream from a coker.The feed characteristics included an API gravity of about 20.3, a sulfurcontent of about 1.2 wt %, a nitrogen content of about 0.57 wt %(including basic nitrogen content between about 1600 wppm and about 1700wppm), an initial boiling point of about 206° F. (about 97° C.), a T50boiling point of about 705° F. (about 374° C.), and a final boilingpoint of about 1188° F. (about 642° C.). The reaction conditions foreach reactor included a pressure of about 1800 psig (about 12.4 MPag), atreat gas rate of about 3300 scf/b (about 558 Nm³/m³) of H₂, a reactiontemperature of about 680° F. (about 360° C.), and an LHSV of about 1.0hr⁻¹.

In FIGS. 2 and 3, as described below, the diamond shapes correspond toReactor 1, which included the gas phase sulfided conventional NiMocatalyst. The squares correspond to Reactor 2, with the liquid phasesulfided conventional NiMo catalyst. The triangles correspond to Reactor3, which included about 25% of the bulk catalyst downstream of about 75%of the conventional NiMo catalyst. Finally, the circles correspond toReactor 4, which included about 50% of the bulk catalyst downstream ofabout 50% of the conventional NiMo catalyst.

FIG. 2 shows the benefit of hydrotreating the feed using at least aportion of bulk metal catalyst. In FIG. 2, the run from Reactor 3(triangles) using a ˜25% loading of bulk metal catalyst shows animprovement in nitrogen removal from about 200 wppm to about 250 wppm,relative to the best performance using only conventional catalyst. Therun from Reactor 4 (circles), using a ˜50% loading of bulk metalcatalyst, shows a further improvement from about 50 wppm to about 100wppm for nitrogen removal, relative to the lower amount of bulk metalcatalyst. The additional nitrogen removal from a relatively highnitrogen feed represents a significant improvement for several reasons.In addition to providing greater removal of contaminants undercomparable conditions, the additional reduction of nitrogen during areaction stage using a bulk metal catalyst can advantageously enhancethe activity of later reaction stages, as the amount, and thusincremental activity suppression, of the nitrogen compounds can beaccordingly reduced/avoided.

The use of the bulk metal catalyst can also provide at least comparableperformance for sulfur removal. FIG. 3 shows the results for sulfurremoval from each of the reactors. The data shows that the reactorsincluding bulk metal catalyst showed at least similar sulfur removaland/or had a small improvement in sulfur removal capability, relative tothe best results using only conventional catalyst. Thus, using a bulkmetal catalyst can improve nitrogen removal for a relatively highnitrogen feed while providing at least comparable sulfur removalcapabilities.

Additionally, the runs including the bulk metal catalyst also showedimprovement in the amount of aromatic saturation. In a fluid catalyticcracking process, typically little or no aromatic saturation occurs.Thus, any additional aromatic removal and/or saturation that can beachieved prior to an FCC process can be particularly beneficial. Arelatively high nitrogen feed can tend to accentuate this problem, asthe relatively high amount of nitrogen can tend to suppress aromaticsaturation activity. Table 1 below shows additional product details forthe products from the four reactors. For each of the runs shown below,the total amount of aromatics in the feed was about 50 wt %.

TABLE 1 Conventional Conventional 75% conv/ 50% conv/ Aromatics wt %(gas sulfide) (liq. sulfide) 25% bulk 50% bulk Mono 32.8 33.5 33.9 33.7Di 4.1 3.9 3.5 3.6 3+ 4.5 13.8 3.3 3.2 Total 41.4 41.1 40.7 40.5 APIgravity 24.8 25.0 25.2 25.3

As shown in the Table above, the runs including the bulk metal catalystshowed reduced totals of aromatics overall, reduced amounts ofmulti-ring aromatics, and improved API values. Note that theconventional catalysts (in Reactors 1 and 2) resulted in saturation orother removal of about 10% of the total aromatics. Use of at least aportion of bulk catalyst (in Reactors 3 and 4) provided an additionalimprovement in aromatics removal from about 0.4 wt % to about 0.9 wt %,corresponding to about a 5-10% improvement in aromatic saturation orremoval. Additionally, the products from Reactors 3 and 4 appear to havean improved distribution of types of aromatics, as the number ofmulti-ring aromatics is reduced in comparison to the runs usingconventional NiMo hydrotreatment catalysts. Since a typical FCC processdoes not typically convert aromatics, the reduced aromatic compoundproduct achieved using the bulk metal catalyst systems represents ahigher value feed for use in an FCC process. It is noted that theboiling point distribution of the product feeds from each of Reactors1-4 was approximately similar throughout the full boiling range.

Example 6 Bulk vs. Supported Catalytic Hydrotreatment Processes

A mineral feedstock (e.g., a vacuum gasoil such as listed in Table 2below) is contacted with a bulk NiMoW catalyst and a commerciallyavailable alumina-supported NiMo catalyst for about 77 days at a varietyof process conditions, such that the bulk catalyst and the supportedcatalyst have a relative volumetric hydrodesulfurization activity ofabout 40% and about 50%, respectively, of that of the respective freshcatalysts of identical composition. About 20 wt % of a biocomponentfeedstock (e.g., a soybean oil such as listed in Table 2 below) can beadded to about 80 wt % of the VGO mineral feedstock to form a mixedfeed, which can thereafter be contacted in a hydroprocessing reactorwith a hydrogen treat gas in the presence of the supported and bulkcatalysts at a temperature of about 680° F. (about 360° C.) and at atotal reactor pressure of about 1280 psig (about 8.8 MPag). The treatgas (−100% hydrogen) was introduced at a rate of about 5900 scf/bbl(about 1000 Nm³/m³). The hydroprocessing reactor had an LHSV of about1.1 hr⁻¹ for the bulk catalyst and about 0.8 hr⁻¹ for the supportedcatalyst. The hydroprocessing was done in parallel pilot unitscomprising a ˜10 cm³ hydroprocessing reactor loaded with an activatedcatalyst based on the commercially available alumina-supported NiMocatalyst, and a ˜7 cm³ hydroprocessing reactor loaded with an activatedcatalyst based on the bulk NiMoW catalyst.

Significant water, CO, and CO₂ were formed during the hydrotreatmentreaction involving the mixed (oxygenated biocomponent-containing) feed,and, under circumstances where some naphtha is also made, such naphthaso formed can be isolated and sent to a mogas pool, if desired, or canbe recycled to another refinery process. At least about 90% of theoxygen from the biocomponent portion of the mixed feed can be removed bythis process.

TABLE 2 Base Feed Biocomponent Mineral feed feed Mixed feed Soybean OilContent — 100 wt % 20 wt % Vacuum Gasoil Content 100 wt %  — 80 wt % APIgravity 28.4 21.7 ~27.1 Sulfur, wppm 26,000 <0.3 ~20,800 Nitrogen, wppm830 14 ~670 Bromine # — 62.6 — IBP, ° F. 570 T5, ° F. 662 T10, ° F. 694T20, ° F. 734 T30, ° F. 766 T40, ° F. 793 T50, ° F. 817 T60, ° F. 840T70, ° F. 865 T80, ° F. 892 T90, ° F. 927 T95, ° F. 950 T99.5, ° F. 10041-Ring Aromatics 14.0 wt %   2-Ring Aromatics 16 wt % 3-Ring Aromatics20 wt % Total Aromatics 50 wt % H₂ Content, mass % 12.1

Each sample feedstock was run for about 2-3 days on oil, and the liquidproduct was sampled periodically (roughly daily). At the end of theperiod on oil for each of the feedstocks contacted with each of thecatalysts, the gaseous products exhibited the properties in Table 3below, which are described on a nitrogen-free, oxygen-free, and hydrogensulfide-free basis. Further, at the end of the periods on oil, theproduct sulfur contents for the mineral only feed were about 1100 wppmfor the supported catalyst and about 520 wppm for the bulk catalyst, andthe product sulfur contents for the mixed feed were about 400 wppm forthe supported catalyst and about 160 wppm for the bulk catalyst.

It is noteworthy that the relative volumetric hydrodesulfurizationactivity of the partially (˜40%) spent bulk catalyst was roughly 1.8 to2.1 times that of the partially (˜50%) spent supported catalyst, whichis roughly consistent with the relative volumetric hydrodesulfurizationactivity ratio of the fresh bulk catalyst to the fresh supportedcatalyst (which varied between about 1.6 and 2.5). As a result of thisobservation, the stability of the hydrodesulfurization activity of thebulk catalyst, relative to that of the supported catalyst, seems to beaffected very little (if at all) by the presence of oxygenated compounds(such as CO and/or CO₂), which can tend to remove/displace sulfuractivating compounds in many hydroprocessing catalysts, thus morequickly reducing activity and/or requiring more (and/or more frequent)addition (e.g., spiking) of activating sulfur compounds into the feed

TABLE 3 Supported NiMo Bulk NiMoW Mineral Mineral feed Mixed feed feedMixed feed Methane (wt %) 0.35 2.16 0.37 1.19 Ethane (wt %) 0.40 0.540.37 0.45 Propane (wt %) 0.68 8.65 0.63 8.12 Isobutane(wt %) 0.11 0.130.10 0.13 n-butane (wt %) 0.55 0.65 0.51 0.71 Isopentane (wt %) 0.200.19 0.19 0.20 n-pentane (wt %) 0.39 0.46 0.37 0.55 C6+ (wt %) 2.70 3.473.48 4.56 Hydrogen (wt %) 94.6 77.2 94.0 73.8 Carbon Dioxide (wt %) 0.03.16 0.0 4.50 Carbon Monoxide (wt %) 0.0 3.37 0.0 5.85

In Table 3, the relative increase in the CO and CO₂ contents of thegaseous products for the mixed feed of the bulk catalyst over thesupported catalyst indicates that the former exhibits more oxygenheteroatom removal (deoxygenation) through decarbonylation and/ordecarboxylation of the biocomponent portion of the feed, whereas therelative decrease in the methane content of the bulk catalyst over thesupported catalyst indicates that the latter exhibits more methanationof the CO/CO₂ byproducts from the biocomponent portion of the feed,which methanation reaction increases hydrogen gas consumption over thecorresponding decarbonylation and/or decarboxylation reaction(s), andwhich methanation reaction can cause and/or exacerbate temperatureexcursions that can detrimentally affect hydroprocessing units and/orcatalytic activity/efficiency/effectiveness.

The principles and modes of operation of this invention have beendescribed above with reference to various exemplary and preferredembodiments. As understood by those of skill in the art, the overallinvention, as defined by the claims, encompasses other preferredembodiments not specifically enumerated herein.

1. A process for hydrotreating a feedstock having a relatively highnitrogen content, comprising: contacting a hydrocarbon feedstock havinga nitrogen content of at least about 3000 wppm with a supportedhydrotreating catalyst under first hydrotreating conditions; andcontacting the hydrotreated hydrocarbon feedstock with a sulfided bulkmetal catalyst under second hydrotreating conditions to produce ahydrotreated effluent, said catalyst comprising a non-noble Group VIIImetal molybdate in which at least a portion, but less than all, of themolybdenum has been replaced by tungsten, wherein the bulk metalcatalyst, prior to sulfidation, is represented by the formula:(X)_(b)(Mo)_(c)(W)_(d)O_(z), wherein X is a non-noble Group VIII metal,the molar ratio of b:(c+d) is from about 0.5:1 to about 3:1, the molarratio of c:d is greater than about 0.01:1, and z=[2b+6(c+d)]/2.
 2. Theprocess of claim 1, wherein the hydrocarbon feedstock has a nitrogencontent of at least about 4000 wppm.
 3. The process of claim 1, whereinthe hydrocarbon feedstock has an API gravity of at least about
 20. 4.The process of claim 1, wherein the hydrocarbon feedstock has a T10boiling point of at least about 300° F. (about 149° C.).
 5. The processof claim 1, wherein the hydrotreated effluent has an API gravity greaterthan about
 25. 6. The process of claim 1, wherein the molar ratio ofb:(c+d) is from about 0.75:1 to about 1.25:1.
 7. The process of claim 1,wherein the molar ratio of c:d is from about 1:10 to about 10:1.
 8. Theprocess of claim 1, wherein at least one of the first hydrotreatingconditions and the second hydrotreating conditions include an LHSV fromabout 0.1 hr⁻¹ to about 2.0 hi', a total pressure from about 800 psig(about 5.5 MPag) to about 3000 psig (about 20.7 MPag), a treat gas rateof at least about 1000 scf/b (about 170 Nm³/m³) using at least 80%hydrogen, and a temperature from about 600° F. (about 316° C.) to about800° F. (about 427° C.).
 9. The process of claim 1, wherein at least oneof the first hydrotreating conditions and the second hydrotreatingconditions include an LHSV from about 0.5 hr⁻¹ to about 1.5 hr⁻¹, atotal pressure from about 1400 psig (about 9.7 MPag) to about 2000 psig(about 13.8 MPag), a hydrogen treat gas rate from about 2000 scf/b(about 340 Nm³/m³) to about 5000 scf/b (about 840 Nm³/m³) using at least80% hydrogen, and a temperature from about 650° F. (about 343° C.) toabout 750° F. (about 399° C.).
 10. The process of claim 1, wherein Xcomprises Ni, Co, or both.
 11. The process of claim 1, wherein X is Ni.12. A process for hydrotreating a feedstock having a relatively highnitrogen content, comprising: contacting a hydrocarbon feedstock havinga nitrogen content of at least about 3000 wppm with a supportedhydrotreating catalyst under first hydrotreating conditions; contactingthe hydrotreated hydrocarbon feedstock with a sulfided bulk metalcatalyst under second hydrotreating conditions to produce a twicehydrotreated feedstock, said catalyst comprising a non-noble Group VIIImetal molybdate in which at least a portion, but less than all, of themolybdenum has been replaced by tungsten, wherein the bulk metalcatalyst, prior to sulfidation, is represented by the formula:(X)_(b)(Mo)_(c)(W)_(d)O_(z), wherein X is a non-noble Group VIII metal,the molar ratio of b:(c+d) is from about 0.5:1 to about 3:1, the molarratio of c:d is greater than about 0.01:1, and z=[2b+6(c+d)]/2;contacting the twice hydrotreated feedstock with a supportedhydrotreating catalyst under third hydrotreating conditions to produceat least a thrice hydrotreated effluent; and delivering the thricehydrotreated effluent to a fluid catalytic cracking stage.
 13. Theprocess of claim 12, wherein at least one of the first hydrotreatingconditions, the second hydrotreating conditions, and the thirdhydrotreating conditions include an LHSV from about 0.1 hr⁻¹ to about2.0 hr⁻¹, a total pressure from about 800 psig (about 5.5 MPag) to about3000 psig (about 20.7 MPag), a treat gas rate of at least about 1000scf/b (about 170 Nm³/m³) using at least 80% hydrogen, and a temperaturefrom about 600° F. (about 316° C.) to about 800° F. (about 427° C.). 14.The process of claim 12, wherein at least one of the first hydrotreatingconditions, the second hydrotreating conditions, and the thirdhydrotreating conditions include an LHSV from about 0.5 hr⁻¹ to about1.5 hr⁻¹, a total pressure from about 1400 psig (about 9.7 MPag) toabout 2000 psig (about 13.8 MPag), a hydrogen treat gas rate from about2000 scf/b (about 340 Nm³/m³) to about 5000 scf/b (about 840 Nm³/m³)using at least 80% hydrogen, and a temperature from about 650° F. (about343° C.) to about 750° F. (about 399° C.).
 15. The process of claim 12,wherein the hydrocarbon feedstock has a nitrogen content of at leastabout 4000 wppm.
 16. The process of claim 12, wherein the hydrocarbonfeedstock has an API gravity of at least about
 20. 17. The process ofclaim 12, wherein the hydrocarbon feedstock has a T10 boiling point ofat least about 300° F. (about 149° C.).
 18. The process of claim 12,wherein the thrice hydrotreated effluent has an API gravity greater thanan API gravity of the hydrocarbon feedstock.
 19. A method foreffectively utilizing heteroatom removal capability of a bulk catalystin removing heteroatoms from a hydrocarbon feedstock, the methodcomprising: hydrotreating a first hydrocarbon feedstock by contactingthe first feedstock with a bulk catalyst containing at least three ofthe following metals: cobalt, nickel, molybdenum, and tungsten, saidbulk catalyst in its unused state having a relative volumetric catalyticactivity for hydrodesulfurization and/or hydrodenitrogenation, with thecontacting being done under conditions effective to at least partiallyhydrodesulfurize and/or hydrodenitrogenate the first feedstock, whereinthe contacting continues until the bulk catalyst exhibits a relativevolumetric hydrodesulfurization activity of not more than 60% of therelative volumetric hydrodesulfurization activity in its unused state;isolating the hydrotreated first hydrocarbon feedstock; hydrotreating asecond hydrocarbon feedstock by contacting the second feedstock with thebulk catalyst whose relative volumetric hydrodesulfurization activity isnot more than 60% of the relative volumetric hydrodesulfurizationactivity in its unused state, with the contacting being done underconditions effective to at least partially hydrodesulfurize and/orhydrodenitrogenate the second feedstock, as well as to hydrodeoxygenatethe second feedstock; and isolating the hydrotreated second hydrocarbonfeedstock, wherein: the second hydrocarbon feedstock contains at least10 wt % more biocomponent content than the first hydrocarbon feedstock;the first hydrocarbon feedstock has a pre-treated sulfur content, thehydrotreated first hydrocarbon feedstock has a post-treated sulfurcontent, and the post-treated sulfur content is no more than 1.0% of thepre-treated sulfur content; the second hydrocarbon feedstock has apre-treated oxygen content and a pre-treated sulfur content, thehydrotreated second hydrocarbon feedstock has a post-treated oxygencontent and a post-treated sulfur content, the pre-treated oxygencontent is no more than 0.5% of the post-treated oxygen content, and thepost-treated sulfur content is no more than 2.0% of the pre-treatedsulfur content; and the isolated hydrotreated first hydrocarbonfeedstock and the isolated hydrotreated second hydrocarbon feedstock areboth combined with a fuel pool.
 20. The method of claim 19, wherein thefirst hydrocarbon feedstock has a sulfur content of at least 500 wppmand is comprised of from 80 wt % to 100 wt % of a diesel boiling rangemineral feedstock and from 0 wt % to 20 wt % of a diesel boiling rangebiocomponent feedstock; wherein the second hydrocarbon feedstock has asulfur content of at least 500 wppm and an oxygen content of at least 1wt % and is comprised of from 10 wt % to 80 wt % of a diesel boilingrange mineral feedstock and from 20 wt % to 90 wt % of a diesel boilingrange biocomponent feedstock; and wherein the contacting in the firsthydrotreatment step continues until the bulk catalyst exhibits arelative volumetric hydrodesulfurization activity of not more than 50%of the relative volumetric hydrodesulfurization activity in its unusedstate.